public class TestPayStrategy {
    public static void main(String[] args) {
        String pay = "aliPay";
        IPayStrategy payStrategy = null;
        if (pay.equals("aliPay")) {
            payStrategy = new AliPayStrategy();
        } else if (pay.equals("wechatPay")) {
            payStrategy = new WechatPayStrategy();
        }

        payStrategy.pay(10);
        payStrategy.queryBalance();
    }
}